DDL conducts both accelerated aging testing and real time aging testing to help establish shelf life and expiration dates for medical devices, packaging and products.
When establishing shelf life claims, it must be recognized that the data obtained from accelerated aging testing is based on conditions intended to simulate the effects of aging on and between the materials involved. The resulting ‘expiration date’ or shelf life from accelerated aging testing is considered a conservative estimate. Real time aging test results are used to verify accelerated aging evaluations and together are used to determine final shelf-life claims/values.
Accelerated Aging Test for Shelf Life Validation
Accelerated aging testing is based on a thermodynamic temperature coefficient formulated by J.H. Van’t Hoff that states “for every ten degree Celsius rise in temperature the rate of chemical reaction will double.” However, since this formula is based on rate kinetics of a single chemical reaction, not on packages made up of various materials, the direct extrapolation of this theory to the aging of packaging materials must be used with caution.
The FDA and the package testing industry believe Van’t Hoff’s theory is useful in defining and justifying accelerated aging testing services. Temperature selection for an accelerated aging study should be determined by the temperature that avoids unrealistic failure conditions such as deformation due to melting. Real time aging must be performed in conjunction with any accelerated aging study to correlate the results found during accelerated aging.
DDL offers Accelerated Aging testing per ASTM F1980. Our technical experts can help you determine the best types of aging variables for your testing project.
Real Time Aging Testing
Real time aging is performed in parallel with accelerated aging in order to support and verify accelerated aging conclusions. It is recognized that in some cases products are technologically obsolete before a real time aging project can be completed.
The FDA provides guidance regarding medical device shelf life determination and advises manufacturers to consider several parameters including chemical and physical. The European Medical Device Directive (MDD) requires all sterile medical devices to have an expiration date. Documented shelf life evidence must exist to substantiate shelf life claims made by the manufacturer.
FAQs on Accelerated Aging
What is Accelerated Aging?
Accelerated Aging is a process of putting packaged products into a chamber, elevating the test temperature to claim a specific expiration date for a medical device product or package. ASTM-F1980 is meant for sterile medical packaging but many companies and or organizations have been using it to claim specific expiration dates for their products.
When to use it?
Primarily medical device manufacturers will use accelerated aging in their package validation to be in compliance with ISO 11607.
How does AA work?
ASTM-F1980 is the standard used for Accelerated Aging of Sterile Barrier Systems and Medical Devices. The theory itself is the Q10 theory, which stipulates that for every 10-degree increase it doubles the reaction rate of the materials. This Q10 factor came from the food industry. This is not an exact science but the FDA allows you to use this theory to get your products to market faster. But you will need to follow it up with real time aging. In doing so, you want to have conclusive evidence that you are not going to have issues with your package or product for that specific shelf life.
Can you use any temperature for AA?
You need to understand where the softening or melting point is before you can pick a test temperature that is going to work properly. Accelerated aging is for homogeneous materials while most medical devices are comprised of multiple materials, which can lead to trouble.
What role does relative humidity play in accelerated aging?
The newly revised ASTM F1980 standard (please see our blog post on the update) now addresses polymers for both the product and the packaging system. With this significant change, medical device manufacturers (MDMs) must consider whether the polymers that make up their product and/or packaging system could be affected by humidity. If any polymers that make up a product or packaging system are considered hydrolytic or corrosive, the use of controlled humidity will be required during accelerated aging (polyamides absorb moisture from the environment and may degrade, while polyolefins will not).
If you have a hydrolytic polymer as part of your product or package system, the standard recommends what humidity to use in section X3.3 (45-55%RH), but ultimately it is up to each medical device manufacturer to determine if that is suitable or not. If you have identified that your polymers do not require humidity, then the use of temperature and ambient RH will be sufficient for your aging studies. Please note that you will need to have a justification in place for whether humidity is needed or not based upon your specific product and packaging system.
What comes after Accelerated Aging?
Accelerated aging is a conditioning step. It does not tell you if you pass or fail your package validation. What comes after accelerated aging indicates if you pass or fail. After accelerated aging comes package strength testing and integrity testing to make sure there is not a sterility breach in the package. If it is product testing, you want to go through all of the tests that you would have done at time-zero or your baseline to ensure aging has not caused adverse effects and compare those results back up.
Why is Real Time Aging important?
Real time aging is critical. If you have a device and that device sits on the shelf with a three-year expiration date, by the time the three years goes by, the product may be obsolete. Accelerated aging thus allows customers to bring products to market faster. Real time aging is definitive data that you are going to get with having your samples stored on a shelf for the same specific expiration date used for accelerated aging.
What are some of the most common issues seen with Accelerated Aging? Planning is the number one issue with accelerated aging. If you need to run a five-year expiration date before next month, there is no physical way to do this. Even if you move the temperature to 100°C. Some may think the answer is to keep moving the temperature up to meet specific needs for the launch date. Putting the samples over 60°C however is a red flag that will come up in regulatory review. As you will run into problems with the product performance and packaging system by choosing a test temperature that is not going to mimic the real world.
Contact us for more information or to talk to an engineer.
The use of Van’t Hoff’s Theory for medical device products and packaging materials is supported by the following references:
Hemmerich, Karl J., “General Aging Theory and Simplified Protocol for Accelerated Aging of Medical Devices” Proceedings MDM-West, January, 1997
Clark, Geoffrey, “Shelf Life of Medical Devices” Guidance Document, Division of Small Manufacturers Assistance, CDRH, FDA, April 1991
